The invention is related to the field of low frequency radiation, and in particular to efficient terahertz sources by optical rectification in photonic crystals.
The terahertz (THz) frequency range can be approximately defined as 3×1011 to 3×1012 Hz, with corresponding wavelengths between 100 μm and 1 mm. Situated in between infrared and microwave frequencies, and in between the reach of photonic and electronic devices, the THz range has not been thoroughly explored because of a lack of good radiation sources and detectors. THz radiation can penetrate into many materials that would be opaque at higher infrared and optical frequencies. At the same time, with a wavelength less than a millimeter, terahertz radiation has an important resolution advantage over the longer wavelength microwave radiation. Consequently, THz radiation is well suited for imaging and spectroscopic applications in the medical, security and manufacturing sectors. Nevertheless, the largest weakness of this field of research is still the lack of a high-power, compact and low-cost source of THz radiation.